1. Field of the Invention
The present invention relates to a hydrogen generator configured to generate hydrogen gas which can be supplied to a fuel cell used to generate electric energy, and a fuel stick used for the hydrogen generator.
2. Description of the Related Art
In portable information devices such as a cellular phone, PDA, digital camera, and the like, a rechargeable battery such as a lithium-ion cell or the like has been mainly used as the power source. In recent years, with the demand for high functionality, multifunctionality, high speed, and long-time operation, a small-sized fuel cell is anticipated as a new power source, and trial manufacture and experimentation have been initiated.
Unlike a conventional rechargeable battery, a fuel cell requires no charging, and it is possible to bring a device into a state where the device can be operated for a long time simply by supplying fuel or replacing the fuel cartridge. Of the available fuel cells, due to the characteristics of a hydrogen-fuel cell using hydrogen as the fuel, which enables a high energy density, application of the hydrogen fuel cell to portable information devices or the like has been studied with a view towards obtaining a fuel cell of similar capacity in terms of peak load capacity as conventional rechargeable batteries. Particularly, in the case of portable information devices, the method of storing hydrogen in a compact and light form is the key to success.
In U.S. Patent Application Publication No. 2005/0227136, filling hydrogen into a tank constituted of a hydrogen storage alloy to use the hydrogen is proposed. However, the hydrogen storage alloy is heavy and the size of the container becomes large, and hence the hydrogen storage alloy is not suitable for portable information devices. Further, when the hydrogen stored in the hydrogen storage alloy is used up, it is necessary to refill the tank with hydrogen by some method. Accordingly, there is a problem that the infrastructure for such purpose must be provided.
In order to solve the problems associated with the hydrogen storage alloy, in WO 02/18267, a hydrogen generator configured to generate hydrogen by thermally decomposing a substance containing much hydrogen, such as ammonia borane, is proposed. According to this method, hydrogen is generated from a solid fuel, and hence a tank made of a large, heavy hydrogen storage alloy is not needed, and it is unnecessary to newly prepare the infrastructure for filling gaseous hydrogen into the hydrogen storage alloy.